Draft gear



Aug. 20, 1940 R. B. coTTRELl. Er AL DRAFT GEAR Filed Feb. v"f, 1938 5 Sheets-5heet lk nue/@w19 if@ er JW @d m Aug 20, 1940- I R. B. coTTRELl. Er A1. 2,212,365

DRAFT GEAR Filed Feb. '7, 1938 3 Sheets-Sheet 2 Allg- 20, l940- R. B. coTTRELL. n AL 2,212,365'

DRAFT GEAR y Filed Feb. Y., 1938 5 .Sheets-Sheell 3 ZQ il@ Patenred'Aug. 2o, 1940 DRAFT GEAR Robert B. Cottrell andfFrederick C. Kulieke, Chicago, Ill., assignors to American Steel Foundries, Chicago, Ill., a corporation of New Jersey Application February 7, 1938, serial No. 189,037

25 Claims.

Our invention relates to railway draft gears of the class generally designated barrel type in which the operating parts are enclosed within a casing or housing.

A general object of our invention is to devise an improved form of draft gear wherein a plurality of sets of rshoes are arranged to operate in series. The generic form of such a type of gear has been more particularly described in the copending application in the name of R. B. Cottrell, Serial No. 172,925, filed in the United States Patent Office November 5, 1937.

Another object of our invention is to device a 1% draft gear of the series wherein the forces of impact and release are transmitted directly from one set of shoes to another without intervening means' such as a wedge block.

Our invention further contemplates a type of draft gear structure wherein the manner of cooperation between the friction producing parts is such `as to reduce to a minimum rictional forces tending to prevent close alignment between the frictional surfaces on the housing and the abutting frictional surfaces of the shoes, thus permitting these surfaces to be in full and even contact throughout the stroke of impact and the movement of release.

Our invention also comprehends a type of gear wherein the number of shoes of each set is such as to admit of relatively greater manufacturing tolerances than is the case in a gear in which vwedging means contacts a greater number of shoes as, for example, three or more.

A specific object of our invention is a design of series cross-equalized type of gear comprising a yplurality of sets of shoes wherein the shoes of one set intervene between the shoes of the other set and wherein the shoes of the respective sets have engagement witheach other along diagonally arranged surfaces.

A still further object of our invention is to design a series crossequalized type of gear comprising a plurality of sets of two shoes each Wherein'each shoe of each set has direct engagement with both shoes of the other set.

A further object of our invention is to devise a gear as above described wherein one set of shoes will have abutment against the compression spring of the gear, the other set of shoes will have abutmenty against the follower wedge (Cl. Z13-32) directly through the successive sets of shoes wlthout intervening means.

Our invention also comprehends a type `of gear wherein the space required for the friction developing shoes is reduced to a minimum by arranging the shoes for direct engagement with each other. v v

Our invention has the further object of designing a gear wherein not more than two shoes have abutment against a single wedging means thereby equalizing the shoe pressures and eliminating the necessity for any such special arrangementsas crowning one or the other of two abutting surfaces in order to secure engagement between a single wedging means and a larger number of shoes as, for example, three or more.. In other words, a natural equalizing arrangement occurs more or less independently of the character of the engaging surfaces when a wedging member is interposed between two shoes.

- Our invention has for a further object a design of'draft gear inra housing of oval shape in which substantially the entire internal` surface at one end thereof will be availed of as a frictional area whereby maximum benefit may be obtained from the draft gear space allotted in the standard A. A. R. car construction. It is well known of course that this standard draft gear pocket is of a rectangular shape having greater width than depth. An oval shaped housing is therefore best accommodated by the standard pocket because it makes maximum use of space available while,` at the same time, approximating the cylindrical shape which offers greatest resistance to bursting pressure.

In the drawings Figure l is a plan view of one form of a draft gear embodying my invention, one-half of the View being in section, the section being taken substantially in the plane indicated by the line l--I of Figure 3;

Figure 21s a side elevation of the gear structure shown in Figure l, half in section, the section being taken in the plane substantially as indicated by the line 2 2 of Figure 3;

Figure 3 is an endvview the View being taken from the left as seen in Figures 1 and 2 and from the outer or open end of the gear, with the follower wedge removed and other parts seated in their normal positions; I

Figure 4 is a fragmentary lsectional vView through two shoes, one of each set, and shows the manner of cooperation therebetween, `the section being taken .longitudinally of the gear and substantially in the plane indicated by the line 4 4 of Figure 3;

Figure 5 is a top plan view of the follower wedge;

Figure 6 is a side elevation thereof, half in section, the section being taken substantially in the plane bisecting the wedge on the long diameter thereof and as indicated by the line S-S of Figure 5;

Figure '7 is an end elevation of the follower wedge, half in section, the section being taken substantially in the plane bisecting the wedge on the short diameter thereof and as indicated by the line l-T of Figure 5;

Figure 8 is an elevational view of the inner face of one Shoe of the outer set;

Figure 9 is an end elevation thereof, the View being taken from the inner end and Figure 10 is a sectional view substantially in the plane bisecting the shoe longitudinally and as indicated by the line IIL-lll of Figure 8;

Figure 11 is an elevational View of the inner face of one shoe of the inner set;

Figure 12 is an end elevation thereof, theview being taken from the inner end ofthe shoe and Figure 13 is a sectional View substantially in the plane bisecting the structure longitudinally and as indicated by the line i3|3 of Figure 1l;

Figure 14 is a fragmentary view of a modified form of our improved draft gear, the view being half in section and corresponding generally to that shown in Figure l;

Figure 15 is a sectional view of the release spring follower used in the modification of our improved form of gear shown in Figure 14, the section being taken substantially in the plane `indicated by the line l5-i5 of Figure l5;

Figure 16 is an end elevation of said release spring follower, the view being taken from th outer end thereof; and

Figures 17 and 18 are transverse sectional views through the housing structure, the section shown in Figure 1'7 being taken nearer the closed end of the housing and substantially in the plane indicated by the line i'i-Il' of Figure 2, and the section of Figure 18 being taken nearer the open end of the housing and substantially in the plane indicated by the line l-i of Figure 2.

Describing our novel gear structure in more detail, it comprises the barrel or housing 2 similar in form to that shown in the co-pending application Serial No. 182,559, filed in the United States Patent Office December 30, 1937, in the name of R. B. Cottrell, said housing having the base flange 4, walls of generally rectangular forrn adjacent said base as most clearly seen in Figure 17, said rectangular shape extending from said base for approximately one-thirdthe length of said housing and merging at the middle portion of said housing into the generally oval-shaped walls, best shown in Figure 18, said oval shape extending from the central portion of said housing to the open end thereof. Centrally formed in the base of the housing is the cavity which forms a convenient receptacle for the head il of the retaining bolt l0, the wallsl of said cavity forming an inwardly projecting stud indicated at I2, said stud providing suitable positioning means for the outer large coil spring I4 and presenting on its inner face suitable seating means for the small inner coil spring I6. Adjacent the base of the housing and in the opposite walls thereof are formed the openings I8 beaded around their edges as at 20, 2t and suitable for drainagel purposes when the assembled gear is stood on end as.

well as facilitating the removal ofcores used in the process of casting housings. Adjacent the open. end of the housing and at opposite sides thereof are formed the relatively wide V-shaped tapering friction faces 22, 22 against which are seated the outer shoes 24, 24 and, likewise, at the intervening sides of the open end of the housing are formed the relatively narrow V-shaped friction. surfaces E6, 26 against which maybe seated the inner shoes 28, 28. The general configuration of the open end of the housing is best seen from a consideration of Figure 3 wherein also may be observed the overlapping relationship of the inner and outer shoes as well as the manner in which the respective sets of shoes are seated against the V-shaped frictionI surfaces of the housing. The outer friction shoes 24, 24 present the diagonal faces 3i), 30 (Figure 2) lvagainst which may be seated the diagonal surfaces 32, 32 presented on the opposite sides ofthe inner face of the follower wedge 34. The outer shoes 24, 24 abut the inner set of shoes along diagonal faces as indicated at 36 (Figure l) and the inner shoes are seated against the outer ends of the `coil springs I4 and vi5 as best seen at 38 (Figures 1 and 2). The follower wedge 34 presents on its outer face the cup-like cavity 4G which forms; a convenient receptacle for the securing nut 42 of the retaining bolt il).

The detailed structure of the follower wedge is shown in Figures 5 to 7 inclusive, wherein it may be observed that itl consists of a generally oval.- shaped cup-like structure` presenting on its inner face the before mentioned diagonal surfaces 32, 32 for engagement with the outer Set yof friction shoes and having on its outer face the oval cavity 4&3 forming a convenient receptacle for the nut of the retaining bolt i as before mentioned. Centrally formed in the base or inner wall of the follower wedge is the bolt opening 44, the smooth outer edges o-f the annular walls of the follower wedge presenting plane surfaces as indicated at 46 for abutment of the usual follower block.

The detail of the outer friction shoe is shown in Figures 8 to 1G, inclusive, wherein it may be observed that the structure comprises a generally tI-shaped outer wall 4l presenting the smooth outer surfaces 48, 48 for abutment against the rl-shaped friction surfaces 22 of the housing and having the relatively heavy body portion 4S with the outer diagonal Vface 35 for abutment of the diagonal face 32 of the follower wedge. vCentrally formed in the body portion 49 is the lightening cavity 5G. The central portion of the base as indicated at 52 lies in a plane substantially at right angles to the axis of the gear, and on opposite sides of said base are formed the diagonally arranged plane surfaces 54, k54 providing abutment for the cooperating surfaces 56 on the inner shoes, Centrally formed on the body portion 48 is a cylindrical groove 58 (Figure`9) providing clearance for the securing bolt i 2 when the parts are in assembled relationship.

The detail of the inner friction shoe is shown in Figures 11 to 13. It will be observed that the shoe is a compact forging having the generally vshaped outer wall Eil presenting the frictional surfaces 62, S2 for abutment against the before mentioned surfaces 26 of the housing (Figure 1).

The shoe also has the relatively heavy central bodyportion 64 with the diagonally arranged outer surfacesi, 5E lying in a single plane and separated by the shallow central groove 56, said y y surfaces 56 having engagement with the surfaces 54 of the respective outer shoes. The inner face of the central body portion 64 presents a surface 68 lying in a plane substantially normal to the axis of the gear.

From a consideration of Figures 9, 10, 12 and 13 it may be observed that the surfaces 48, 48 of the outer shoes and 62, 62 of the inner shoes have a slight taper with respect to the aXis of the gear, thus accommodating themselves more readily to the form of the internal surface of the housing at the frictional end thereof.

Figure 14' shows a gear generally similar to that shown in Figures 1 to 3 with the housing 2, the inner friction shoes 28, 28 and the outer friction shoes 24, 24, the follower wedge 34 and the retaining bolt Ill, all substantially identical to the corresponding parts of the gear shown in Figures 1 to 3.- Inthis modification, however, I have provided the large outer compression spring I I4, the intermediate compression spring I I6 and a release spring I I8. vThe large and intermediate compression springs |l4'and IIS have abutment againstthe inner shoes 28, 28 as at 38. The release spring I I8 has abutment as at |20 against the inner flanged end of the release spring follower |22, the opposite end of whichv has abutment as at |24 against the follower wedge 34, thus'facilitating the opening of the gear after a compression stroke. The form of the release spring follower |22 is shown in Figures 15 and 16 wherein it may be observed that it comprises a thimble flanged at the inner end as atI26 for abutment of the release spring ||8 and presenting a smooth annular surface at the opposite end as at |28 for abutment of the follower wedge 34, the central opening |30 permitting said follower to be sleeved uponthe securing bolt I0 as a convenient retaining means: therefor.

From the foregoing it will be apparent that the diagonal faces 32, 32 on opposite sides of the follower wedge engage diagonal faces 30, 30 on the outer shoes in two planes, said planes intersecting inV a line traversing the long diameterof the housing and, therefore, at right angles to the axis of the gear; also that the diagonally arranged surfaces 56, 56 of the inner friction shoes engage the frictionsurfaces 54, 54 on the outer friction shoes in two planes which intersect in a line traversing the short diameter of the housing and, likewise, perpendicular to the axis of the gear. f

It is to befunderstood that we donot wish to l be limited by the exact embodiment of the device shown which is merely by way of illustration and not limitation as various and other forms of the device will of course be apparent tothose skilled in the art without departing fromA the spirit of the invention or the scope of the claims.

1. In a friction absorbing vdevice a housing having inner friction surfaces adjacent the open end, resilient 'means,' a wedgefollower, and outer vand inner sets of shoes in alternate arrangement against said surfaces,` each'shoe of each set having abutment with-a Yplurality of shoes of another set 'whereby the forces of impactand release are transmitted from said foilower directly through said shoes to said resilient means. l

2. In a friction absorbing device a housing having an oval-shaped friction end with internal friction faces, resilient meansafollower wedge, and a plurality of sets of shoes in alternate arrangement within said oval end, one set' of said shoeshaving'abu'trnent againstfsaid wedge, another set of said shoes abutting' said means, the

sets of said shoes abutting each other on faces lying in two planes which projected intersect on the shortl diameter of said oval end.

3. In a friction device a housing having an oval friction end with V-shaped internal friction surfaces, resilient means, a follower wedge, and sets of shoes in alternate arrangement against said surfaces, said sets of rshoes beingarranged in series between said wedge and said means with the shoes of one set abutting said wedge, the shoes of the other set abutting said means, and the sets abutting each other on faces lying in two planes which projected intersect on the short diameter of said oval end.

4. In a friction device a housing having an ovai friction end with internal friction surfaces, resilient means, a follower wedge, and a plurality of sets o-f shoes in alternate arrangement against said housing betweenv said wedge and said means,

plurality of sets of friction shoes seated in alternate 4arrangement against said surfaces, resilient means and a wedge follower in abutment with said sets respectively, each shoe of each set having engagement with two shoes of another set whereby the forces ofimpact and release are equalized among said several shoes.

6. In a friction absorbing device affording direct engagement between respective sets of shoes by interposing each shoe of each set between a plurality of shoes of another set, afhousing having an oval open end with two pairs of opposed internal friction surfaces extending substantially therearound and aligned along the long and short axes of said oval end, said axes being sub.- stantially at right `angles to each other, resilient means, a follower wedge, and` two sets of vshoes arranged in series between said wedge'an'd said resilient means'and against said pairs of friction surfaces respectively with each shoe of each set having abutment against both shoes of the other set, said shoes occupying substantially the entire frictional are-a around the friction end of said housing, the shoes of one set abutting said wedge on diagonally outwardly directed faces and abutting the shoes of the other set on diagonally inwardly directed faces, whereby the forces ofv impact and release are transmitted directly from said wedge through said shoes to said means. i

'7. In a friction absorbing device affording direct thrust from one'I set of shoes to another thereof, an oval housing having two sets of internal tape-ring friction surfaces extending substantially around'the open end thereof, two sets of shoes arranged in series and alternately seated against said surfaces on axes substantially at right angles. to each other and occupying substantially all of said friction'surfaces, a wedge follower, and resilient means, one set of said shoes having abutment against said follower wedge and the other set of said shoes abutting said resilient means, both shoes of each' set having abutment with both shoes of the other set along planes diagonal with respect to the axis of said gear, whereby forces of impact 'are trans* mitted through one set of shoes directly to the ternal friction surfaces extending substantially therearound, one set of said surfaces being on the long axis and theother set on the short axis thereof, two sets of diametrically opposed friction shoes alternately arranged. against said surfaces and utilizing substantially all of the frictional area of said oval end, the shoes of respective sets being in overlapping relationship longitudinally of said gear, a wedge follower, and resilient means, one set of said shoes having abutment with said wedge follower, the other set of said shoes abutting said resilient means, the engaging surfaces between the shoes of respective sets being along .diagonal planes, whereby the forces o-f impact and release are transmitted directly from said wedge through said shoes to said means.

9. In a friction absorbing device, a housing having internal tapering friction surfaces substantially surrounding the open end thereof, said surfaces being arranged in. opposed pairs along axes substantially at right angles tol each other,

- sets of shoes arranged in series and alternately seated against said surfaces with the shoes of the respective sets arranged' against said housing in overlapping relationship longitudinally of said housing, one set of said shoes abutting said fol- Y lower and the other set abutting said. means, each shoe of each set having abutment with both shoes of the other set.

10. In a friction absorbing device, a housing having substantially continuous internal tapering friction surfaces around the oval ope-n end thereof, said surfaces being arranged in two sets along axes substantially atright angles toeach other, resilient means, a wedge follower, and two sets' of shoes arranged in series between said means and follower with the shoes of respective sets alternately seated against said friction sur-` faces in overlapping relationship longitudinally of said housing and utilizing substantially all of the frictional area thereof, the shoes of one set abutting sai-d resilient means and the shoes of the other set abutting said follower, each shoe of each set having wedge abutment between the shoes of the other set.

11. In a draft gear a housing having internal friction surfaces, resilient means, a wedge follower, and outer and inner sets of friction shoes arranged in tandem and seated'in alternate formation against said surf-aces, each shoe of each set having abutment against 'two shoes of another set, one set of said shoes having abutment with said follower wedge and another set of said shoes having abutment with said resilient means.

12. In a friction device a barrel housing having an internal oval friction end, resilient means, a follower wedge, and a plurality of sets of shoes in alternate arrangement within said oval end, one set abutting said wedge, another set abutting said means, and each shoeof each set abuttinga plurality of shoes of another set along surfaces lying in planes which projecting intersect on the short diameter of said oval end. i

13. In a friction device a housing having an interval oval friction end with V-shaped friction surfaces, resilient means, a follower wedge, and sets of shoes in alternate arrangement against 15. In a friction device a barrel housing having l an internal oval friction end, resilient means, a follower wedge, and a plurality of sets of shoes in alternate arrangement withinsaid oval end, one set abutting said wedge, another set abutting said means, and each shoe of each set abutting a plurality of shoes of another set.

16. In a friction 'absorbing device a housing having internal friction surfaces adjacent the open end, resilient means, a wedge follower, and outer and inner sets of shoes in alternate arrangement against said surfaces between said means and said follower, each of said shoes having abutment with a plurality of shoes in a different set. v

17. In a friction absorbing device, a housing having inner friction surfaces adjacent the oval open end thereof, resilient means, a wedge follower, and a plurality of sets of shoes in alternate arrangement against said surfaces, each shoe of each set having abutment with a plurality of shoes of another set whereby the forces of impact and release are transmitted from said follower directly through said shoes to said resilient means, said abutting surfaces at opposite sides of the device defining planes which intersect on the short axis of said oval end.

18. In a friction absorbing device, a housing having inner friction surfaces adjacent the open oval end, resilient means, a wedge follower, and a plurality of sets .of shoes in alternate arrangement kagainst said surfaces having an overlapping relationship longitudinally of said housing, each shoe of each set having abutment with a plurality of shoes of `another set whereby the forces of impact and release are transmitted from said follower directly through said shoes to said resilient means, said abutments at opposite sides of said device defining planes which intersect on the short axis o-f said oval end.

19. In a friction absoribing device, a housing having anoval-shaped friction end with a pluralityv of V-shaped internal friction surfaces, a plurality of sets of friction shoes seated in lalternate arrangement against said surfaces, resilient means, and a wedge follower, eachshoe of each set engaging two shoes of another set whereby the forces of impact and release .are equalized among said several shoes, said engaging surfaces lying in planes projections o-f which intersect on the short axis of said oval end.

20. In a draft gear, a housing having an oval openend with internal friction. surfaces, resilient means, a wedge follower, and outer and inner sets of friction shoes arranged in tandem and seated in `alternate formation against said surfaces, each shoe of each set having abutment against two shoes of another set, one set of said shoes having abutment with said follower wedge and anotherv set of said shoes having labutment with said resilient means, theabutting surfaces between the shoes of said respective sets defining two planes which projected intersect on the short axis of said oval end.

21. In a draft gear, a housing having an oval open end with internal friction surfaces, resilient means, a wedge follower, and outer and inner sets of friction shoes arranged in tandem and seated in alternate formation against said surfaces, each shoe of each set having abutment against two shoes of another set, one set of said shoes having abutment with said follower wedge and another set Iof said shoes having abutment with said resilient mean-s, the engaging surfaces between said follower wedge and the abutting shoes lying in two planes which projected intersect -on the long axis of said oval end.

22. In a friction absorbing device, a barrel housing having a generally ova-l open endl with sets of opposed tapering friction surfaces arranged substantially therearound, the surfaces of each set being arranged along one axis of said oval end., and clutch mechanism vcomprising set of surfaces being arranged along one axis of said oval end, and clutch mechanism comprising a wedge, resilient means .and sets of shoes interposed between said Wedge and `means and seated respectively against said sets of surfaces, each shoe of each set having abutment with both shoes of the other set.

24. In a friction absorbing device of the barrel type, a housing having an oval open end with pairs of opposed 'tapering internal friction sur; faces extending substantially therearound, each` set of surfaces being arranged along one axis of said oval end, and clutch mechanism comprising a wedge, resilient means and sets of shoes interposed between said wedge and means and seated respectively against said sets of surfaces, both shoes ofv each set abutting both shoes of the other set.

25. In a friction absorbing device of the barrel type, a housing having an oval open end with pairs of opposedtapering internal friction surfaces extending `substantially therearound, each set of surfaces being arranged 'along one axis of said oval end, and clutch 'mechanism 'comprising a wedge, resilient means and sets of shoes interposed between said wedge and means and seated respectively against said sets of surfaces, eachshoe having abutment with two shoes of the other set.

ROBERT B. COTTRELL. FREDERICK C'. KULIEKE. 

